Communicating data without some measure of their precision can lead to misinterpretation and incorrect inferences. Several conventions for displaying error along with the data they modify are described and illustrated. Alternatives are offered that seem to provide improvements in the effective communication of error as well as increasing their…

The National Assessment of Educational Progress (NAEP) is an enormous and enormously ambitious project. It generates data of a richness and complexity beyond any simple survey. The broad utilization of the information it provides can be aided through the use of more evocative data displays. In this report, the uses to which data tables are put is…